<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title></title>
	</head>
	<body>
		<script>
			alert(fn(10,5,test1));
			
			function fn(num1,num2,demo){
				return demo(num1,num2);
			}
			function test1(a,b){
				return a+b;
			}
			function test2(a,b){
				return a-b;
			}
			function test3(a,b){
				return a*b;
			}
			function test4(a,b){
				return a/b;
			}
		</script>
	</body>
</html>
